Alcohol amnestic disorder is characterized primarily by memory difficulties. The word amnesia means "without memory". Unlike psychogenic amnesia, the memory problems associated with alcohol amestic disorders are general, not specific to the individual's sense of identity. The disorder was first studied by the Russian neurologistSergei Korsakoff over one hundred years ago. An older name for the condition is Korsakoff's psychosis. Alcohol abuse tends to induce a deficiency of thiamine, a B-complex vitamin. Some of the impairment associated with alcohol amnestic disorder is reversible with vitamin therapy. On the other hand, some of the impairment is due to the loss of neurons linked to the toxic effects of alcohol. Impairment associated with destroyed neurons is not reversible.